ND hockey was in a league with Minnesota, Michigan, MSU, and Wisconsin in the 1970s (the WCHA) and then in a league with Michigan, MSU, OSU, etc., from the 1980s until 2013 (the CCHA). That league then fell apart when Penn State went to D1 hockey and the Big 10 therefore sponsored hockey (meaning that six Big 10 schools had hockey, which is enough for the conference champion to get an auto-bid to the NCAA tournament). So the Big 10 teams in ND's league left, the league fell apart, and ND was left to find a new conference.
Hockey East is a great conference -I would rather stay, personally- but the geographic problem is too great, even in the new world of big conferences. All of the schools save ND are in New England. It doesn't really make a ton of sense, it means you either play a team at home or on the road, while other teams play home-and-homes, etc.
Hockey is unique because (1) only 60 schools have D1 hockey; (2) only 15 of those have D1 FBS football, and only 9 of those are in P5 conferences or are ND; and (3) all but 5 D1 hockey schools are limited to the Northeast and the upper Midwest. So the conference situation has always been different and probably always will be. The Big 10 is as of yet the only P5 conference sponsoring hockey and I doubt that will change anytime soon. Obviously, any association with the Big 10 is to be avoided, but this is increasingly looking like the best option, given what happened after the CCHA fell apart.
